Risley rotary prism

Ris·ley ro·ta·ry prism

(riz'lē),
a prism with a circular base that is rotated in a metal frame marked with a scale; used in examination of ocular muscle imbalance.

Ris·ley ro·ta·ry prism

(riz'lē rō'tŏr-ē prizm)
A prism with a circular base that is rotated in a metal frame marked with a scale; used in examination of ocular muscle imbalance.

Risley,

Samuel D., U.S. ophthalmologist, 1845-1920.
Risley pliers
Risley rotary prism - used in examination of ocular muscle imbalance.